Multiple input, multiple out technology, also known as MIMO technology, is making it possible for data speeds to be faster than ever before so we can transfer greater amounts of data. However, as with all wireless technologies, compliance testing is required to ensure that devices using these technologies function properly and don’t pose any harm to consumers. To learn everything you need to know about MIMO technology, OTA testing, and SAR testing, keep reading.

What is MIMO?

Wireless devices that use MIMO technology use multiple antennas to both transmit and receive information. By combining multiple antennas, data speeds and transmission capacity are optimized while minimizing errors to allow data to travel over more than one signal path simultaneously. 

The multiple antennas used in MIMO can boost the capacity of radio frequency systems, creating a more stable connection with less congestion. Other antenna technologies that create more than one version of the signal also increase the signal-to-noise ratio and the error rate of the signal.

What is MIMO used for?

This technology is used to power Wi-Fi, 4G, LTE, and 5G technologies. MIMO is most often used to allow high-bandwidth communications without interference from microwave or RF systems. An example of when this may be necessary is for first responders that need to communicate during a disaster or power outage when cell networks may be down or overloaded.

OTA Testing for MIMO Technology

Over-the-air (OTA) testing is a method used to forecast the performance and reliability of wireless devices in the real world. To conduct this testing, the device is placed in a free-space environment within a test chamber, where real-life situations are simulated.  The device is then subjected to multiple test conditions to observe how it responds to each situation. This testing measures the device’s signal path and antenna performance to ensure that the tested device will be able to perform as intended.

Products that use MIMO technology may include phased antenna arrays of 4-by-4 or 8-by-8, making it necessary to determine how to conduct SAR testing for these devices based on OTA testing. There are three different distances of testing: near-field reactive, near-field radiative, and far-field.

• Near-field reactive testing is close enough that physical obstructions could affect the signal.
• Near-field radiative is testing in which an obstacle may still be able to distort the signal
• Far-field is testing in which the device’s signal simply radiates out with a square-law power decay.

A particular concern when conducting compliance testing for devices using MIMO technology is that all testing is conducted in the near-field reactive region. Testing radiated signals also raises the challenge of ensuring that stray signals won’t obscure SAR testing results for these devices. 

It’s necessary to figure out how to test these devices in a functional environment that won’t have outside interference or allow signals to be transmitted externally. This requires the use of specific testing chambers for MIMO devices. Overall, SAR testing for these devices does require changes in how this testing is conducted.

Testing For MIMO Technology and More at RF Exposure Lab

Our team’s expertise comes from RF Exposure Lab’s Owner, Vice President, and Chief Engineer, Jay Moulton. An authority in SAR testing with a background in manufacturing and the regulatory side of SAR testing, Jay Moulton has more than 25 years of experience. He is unique in his ability, experience, and knowledge of SAR. It’s this distinctive expertise and knowledge that allows us to guarantee our clients accurate SAR testing results and solutions.

In addition to this expertise, our team always goes above and beyond, making sure that our clients understand how we are testing their devices and how SAR standards affect this. We strive to be as communicative and transparent as possible throughout the testing process so our clients are always up to date on the status of their testing.

We offer SAR testing services for a variety of wireless devices, such as

• Millimeter wave devices
• Near field charging devices
• Cell phones, laptops, and tablets
• Medical devices
• Modems

As well as many more devices! If you’re looking for SAR testing help that is provided with expertise, speed, accuracy, and integrity, contact us to learn more about our services or to get a quote.